Module mmdb.MaxMindDB

The following simple changes were made after generating the bindings

1. type mmdb_uint128_t is defined as ubyte[16], becuase DLang currently doesn't support 16 byte integers natively.

2. union member of MMDB_entry_data_s had to be aligned manually to 16 bytes boundary

3. import core.stdc.stdarg : va_list was added